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Thread: Freesat EPG in UK

  1. #1
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    Freesat EPG in UK

    Hi,

    as some of the UK users here will be aware BBC/ITV will be launching a freesat service hopefully sometime in May. The channels themselves will be the ones as per FTA on Sky I think but the epg will be new so I wondered if Sub has any plans to add support for it once it goes live? At the moment all we can get is now/next via existing epg as SKY have their own propriety EPG.

    Thanks

  2. #2
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    I see MythTV have implemented support for this. Apparently it's just a normal EIT, with Huffman compression on the data for which they've already worked out the tables.

  3. #3
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    Yes I see you are a user on DS too As you can see there someone has already written an app to extract the epg info to xmltv file so maybe sub might have a look at this sometime in the future?

  4. #4
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    I think this is the thread that details the Freesat EPG tool:
    http://www.digitalspy.co.uk/forums/s...hp?t=837707ink
    It would be great if it could be made to work with GBPVR - especially as they seem to keep changing the Freesat stuff at the moment. The way the Freesat boxes work is they take all the tuning settings from the EPG - so box owners never have to rescan or change pids etc.
    Last edited by Pob; 2008-07-27 at 11:02 PM.
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  5. #5
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    I would very much love to see GBPVR being able to obtain the EPG from the transmission stream. It would make thinks very easy especially for my dad who doesn't have an internet connectin and is unable to download his TV listings.
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  6. #6
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    I've noticed that DVBGuide can now read the EPG stream and produce an XMLTV file - just set it up as a scheduled task to run before you do the EPG import and you should be set. Note I haven't tried it yet as I seem to be permanently rebuilding my box.

    Sub - for your notes, some info from the README on the freesat EPG:

    Freesat EPG
    ~~~~~~~~~~~
    Using DVBGuide to capture the United Kingdom's Freesat EPG data is complicated by the fact that the data is present on non-standard PIDs. Command line options are present to specify these PIDs. These PIDs actually vary according to which transponder is being tuned to.

    It is not currently necessary to set the PID for NIT capture (although a command line option is provided in case that becomes necessary).

    On the main Arqiva transponder (11.426 GHz, horizontal) the Freesat BAT & SDT data is present on PID 3002. The EIT data is present on PID 3003. On most of the other transponders the data is present on PIDs 3841 (BAT & SDT) and 3842 (EIT).

    Full information on tuning parameters and the Freesat PIDs used may be found on various web sites and discussion forums. However, unless problems are found, it is recommended that the main Freesat transponder is used for EPG capture for the simple reason that the EPG data repeats every 30 seconds. I.e. it takes just 30 seconds to perform a full EPG capture. On the other transponders the repetition rate is much slower and it can take nearer 30 minutes to perform the same capture.

    A sample batch file is provided to show how to capture Freesat EPG data. All being well, this should result in around 27,000 EPG records captured in 30 seconds.


    Freesat text compression
    ~~~~~~~~~~~~~~~~~~~~~~~~
    The Freesat EPG data uses a text compression scheme that is a variant of the first order Huffman compression used for ATSC EPG data. It differs from the specified ATSC scheme though by using compression tables that are optimised for the character pairings found in typical United Kingdom EPG data. Unlike the ATSC data tables, those for the Freesat scheme have not yet been made public. It has therefore been necessary to derive the code tables by observation of the received bit stream.

    There are two main code tables: one optimised for use on programme titles and the other for programme descriptions. The tables are normally used as such but occasionally the titles table is used to compress the description part. Similarly, the description table is sometimes used to compress the titles field. Occasionally (and usually for very short titles such as "ER" or "Coast") neither compression scheme is used and the data is present as plain text (as described in the DVB standard).

    Each of these two code tables contains entries for each pair of characters used in the plain text. For example, to decode a bit stream into the word "Freesat" requires table entries corresponding to the character sequences "Fr", "re", "ee", "es", "sa" and "at". Two additional entries in the table are also required for the character pairings at the start and end of the word (i.e. "?F" and "t?" where ? represents the character either side of the word in the plain text).

    The above should serve to illustrate that the code tables are large with a great many data points corresponding to all possible character sequences (remember, it's not just alpha characters but numbers and punctuation too). Without an official specification the decode tables have had to be constructed by observing the Freesat EPG data over the last two months.

    Although there are still many missing data points in the decode tables used by DVBGuide these do correspond to rare and unusual character sequences. Consequently, although the tables may only be 50% complete (a guess since, without the specification it is impossible to be sure how many data points there are in the full tables) these partial tables will decode around 95% or greater of the EPG text. In a typical capture of around 27,000 EPG entries the current decode tables only fail on a few hundred titles or descriptions.

  7. #7
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    Currenlty using XMLTV Gui for epg data but this doenst have a lot of the freesat channels, what my best option at the moment Digiguide?
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  8. #8
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    Digiguide pretty good for missing channels from RT, but they don't have them all.

    There is also another way to grab xml at the moment but I think those that have it are keeping quiet
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  9. #9
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    Quote Originally Posted by steeb View Post
    There is also another way to grab xml at the moment but I think those that have it are keeping quiet
    There's no secret about this one http://www.digitalspy.co.uk/forums/s...d.php?t=823104

    Grabs it off Sky's tvguide.


    I'm not sure how controllable it is.


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